Question

In an industrial process 10 kgs of water per hour to be heated from 20 degC to 80 deg C. Steam at 150 deg C passes from a boiler into a copper coil immersed in water. The steam condenses at coil & return to boiler at 90 deg C. How many kgs of steam is required per hour to do the job. Take specific heatof steam is 1 cal/kg/deg C & latent heat of steam is 540

Answer 1

$$\begin{gathered} LetthemKgamountofsteamrequiredtoraisethetemperatureof10Kgofwaterfrom20°Cto80°C. \\ Theamountofheatlostbysteamfrom150°Cto90°C=m\times 1\times \left(150°-100°\right)+m\times 540+m\times 4200\left(100°-90°\right) \\ =50m+540m+42000m=42590m \\ Theamountofheatgainedby10Kgofwater=10\times 1000\times \left(80°-20°\right)=10\times 1000\times 60 \\ Butamountofheatgained=amountofheatlost \\ i.e.42590m=10\times 1000\times 60 \\ orm=\frac{10\times 1000\times 60}{42590}=14Kgofsteam \end{gathered}$$